4 - Hypertension and Heart Failure Drugs Flashcards

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1
Q

What are the effects of hypertension and how is bp regulated?

A
  • Increases arterial wall thickness by remodelling and hypertrophy. Stiffens the walls so they are less compliant
  • Organ damage from lack of blood flow
  • Regulated by RAAS, autonomic NS, bradykinin, NO and natriuretic peptides
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2
Q

What are the values that define hypertension and what are some of the causes?

A

>140/90

primary, secondary (conn’s, diabetes), isolated diastolic/systolic, white coat

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3
Q

What are target blood pressures (clinically and ambulatory) for different groups of people?

A
  • <140/90 if less than 80 inc type II diabetes
  • <150/90 if greater than 80
  • <135/85 if type I diabetic
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4
Q

What is best practice when diagnosing hypertension?

A
  • Sitting relaxed and arm supported
  • Both arms should be within 15mm/Hg of each other, if not then repeat. Take highest reading
  • Measure over a period of time including ambulatory and hoe machines
  • CVD and organ damage should be assessed whilst waiting for hypertension confirmation
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5
Q

What are the stages of hypertension?

A
  • Resistant hypertension at stage 3
  • Emergency if >180/20 and clinical signs
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6
Q

What is prehypertension and how can progression of this be limited

A

>120/80 but less then 140/90

  • Promote regular exercise
  • Healthy balanced diet
  • Reduce stress and increase relaxation
  • Limit alcohol and caffiene intake
  • Smoking cessation
  • Reduce salt in diet
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7
Q

In general what are some classes of drugs that are used to treat primary hypertension?

A
  • ACE inhibitors
  • ARBs
  • Calcium channel blockers
  • Diuretics
  • Alpha and Beta blockers
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8
Q

What is the mechanism of action of ACEi’s to treat hypertension?

A

Competitive inhibitors of Angiotensin Converting Enzyme:

  • Reduce formation of angiotensin II
  • Arteriole vasodilation
  • Reduce circulating aldosterone so less ADH
  • Build up of bradykinin which is a vasodilator as makes NO, good for low renin hypertensives
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9
Q

What are some examples of ACEi’s?

A
  • Ramipril
  • Lisinopril
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10
Q

What are some side effects of ACEi’s?

A

Side effects:

    • Dry cough*
  • Hypotension
    • Hyperkalaemia* as loss of aldosterone
  • Renal failure especially due to renal artery stenosis as efferent arteriole needs to constrict
    • Angiooedema* due to BK, especially black population
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11
Q

What are some contraindications of using ACEi’s?

A
  • Pregnancy (along with ARBs, can cause CVS and CNS defects and growth restriction and oligohydraminos)
  • Hyperkalaemia

- NSAIDs, K+ raising drugs, antihypertensives

  • AKD
  • Breastfeeding
  • Renal artery stenosis
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12
Q

What is the mechanism of action of ARBs?

A

- AngII mainly binds to AT1 receptor

    • Inhibits vasoconstriction* better than ACEis as the AT1 receptor blocked so any AngII made from chymases can not work either
    • Inhibits aldosterone stimulation*
  • Less effective in low renin hypertensives as no effect on bradykinin
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13
Q

What are some examples of ARBs?

A
  • Candesartan
  • Losartan
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14
Q

What are some side effects and contraindications of ARBs as antihypertensives?

A

Side effects:

  • No dry cough and angiooedema like ACEi
  • Renal failure
  • Hyperkalaemia

Contraindications:

  • AKD
  • Pregnancy and breast feeding
  • Renal artery stenosis
  • K+ raising drugs, NSAIDs, other antihypertensives
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15
Q

What is the mechanism of action of calcium channel blockers?

A

- Bind to alpha1 subunit of L-type calcium channel (VOCC), reducing cellular calcium entry causing vasodilation, reducing preload on the heart

  • LTCC in vascuar smooth muscle, cardiomyocytes, SA and AV node. Different classes selective for different areas
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16
Q

If a patient had hypertension with low renin levels, what class of drug would be best to prescribe them first?

A

- CCB as doesn’t target RAAS

  • ACEi as increases bradykinin
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17
Q

What are the three main classes of CCBs and give some examples for each?

A

- Dihydropyridines: amlodipine (long half life), nifedipine (selective for cerebral vasculature so used for subarachnoid haemorraghe), nimodipine

- Benzothiazapines: Diltiazem

- Phenylakylamines: Verapamil

18
Q

Where do each of the classes of CCBs work in the body?

A

- Dihydropyridines: 1st line CCB most commonly used for hypertension. Selective for peripheral vasculature but little ino/chronotropic effect

- Phenylalkyamines: mainly act on myocardium, depress the SA node and slows AV conduction so negative inotropy. Used for SVTS. Can worsen HF so don’t give to a hypertensive with heart failure

- Benzothiazapines: Sit in the middle, act on myocardium and vascular smooth muscle, can worsen heart failure

19
Q

What are the side effects and contraindications of the use of dihydropyridines (good oral absorption) for hypertension?

A

Side effects:

  • Ankle swelling, flushing and headaches from vasodilation
  • Palpitations as compensatory tachycardia

Contraindications:

  • Unstable angina and severe aortic stenosis as the palpatations
  • Amlodipine and simvastatin as increased effect of statin
  • Other antihypertensives
20
Q

What are the side effects and contraindications of the use of phenylalkylamines?

A
  • Mainly used to treat arrhythmias (SVTs) and angina not HTN

Side effects:

  • Constipation, bradycardia, heart block, cardiac failure

Contraindications:

  • Poor LV function
  • AV nodal conduction delay
  • B-blockers, other antihypertensives, other antiarrhytmic agents
21
Q

What are the properties and adverse effects of Benzothiazepines e.g. diltiazem?

A

- Properties (same as phenylalkylamines): impedes calcium transport across the myocardial and vascular smooth muscle cell membrane, peripheral vasodilation, ↓ myocardial contractility

- Adverse effects: bradycardia, can worsen heart failure

22
Q

What thiazide/thiazide-like diuretics are used to treat hypertension and what is their mechanism of action?

A

Reduce distal tubular sodium reabsorption by blocking NaCl channel

  • Initial blood volume decrease
  • Later, total peripheral resistance falls
  • RAAS compensates
  • Useful over CCBs in oedema
23
Q

What are some examples of thiazides?

A
  • Bendroflumethiazide
  • Indapamide (thiazide like)
24
Q

What are some side effects and contraindications associated with the use of thiazides in treating hypertension?

A

Side effects:

  • HypoK, hypoNa, hyperuricemia
  • Arrhythmia
  • Increased glucose
  • Increased cholesterol and triglycerides

Contraindications:

  • HypoK, HypoNa
  • Gout
  • NSAIDs, K+ lowering drugs
25
Q

What are the steps recommended by NICE in treating primary hypertension?

A

- ACD rule with step 4 considering:

  • alpha/beta blocker/other diuretics
  • adherance of patient
  • referral to expert advice
26
Q

Why are hypertensive type II diabetics treating with an ACEi first regardless of age?

A
  • ACEi are antiproteinuric! Stops progression of diabetic nephropathy
27
Q

What diuretics, other than thiazides, are added in step 4 of treating hypertension and what are the contraindications of this drug?

A

- Spironolactone: aldosterone receptor antagonist

- Contraindications:

  • Hyper K
  • Addisons
  • K+ raising drugs, ACEis, ARBs
28
Q

If a patient is at step 4 of treating hypertension but has hyperkaelamia, what other drug can be added to their regimen?

A
  • NOT spironolactone as hyperkalaemic
  • Add alpha or beta blocker
29
Q

What is a centrally acting drug?

A
  • Lowers heart rate and reduces blood pressure by blocking sympathetic nervous system
  • e.g Labetalol in pregnancy or hypertensive emergency
30
Q

What are the actions of betablockers and some examples?

A
  • Reduce HR and CO
  • Inhibit renin release
  • Initially TPR increases later falls to normal
  • Labetalol, bisoprolol, metoprolol
31
Q

What are some side-effects and contraindicaitons of the use of beta blockers?

A

Side effects:

  • Heart block
  • Lethargy
  • Impotence
  • Bronchospasms
  • Bradycardia
  • Impaired glucose tolerance

Contraindications:

  • Asthma
  • Hepatic failure
  • Non-dihydropyridine CCBs as asystole
32
Q

What are the mechanisms of actions of alpha receptor blockers? e.g doxazosin

A

- Selective antagonism of a-1 adrenoreceptors can be used for BPH and HTN

  • Antagonise contractile effects of NA on vascular smooth muscle
  • Reduce peripheral vascular resistance
  • Benign effect on plasma lipids / glucose
33
Q

What are some side effects and contraindications of the use of alpha blockers?

A

Side effects: postural hypotension so dizziness, syncope, headche and fatigue, oedema

Contraindications: postural hypertension or taking dihydropyridine CCBs

34
Q

What are the causes of heart failure and how can non-pharmacological treatment help to alleviate symptoms like oedems, dyspnoea?

A
  • Ischaemic heart disease
  • Hypertension
  • Valve disease
  • Reduce salt intake, exercise and stop smoking and drinking alcohol
35
Q

In four steps, describe the clinical management of heart failure

A
  • Diuretics
  • ACE inhibitor
  • ARB
  • β-blocker
  • Spironolactone

Drugs are given to help sympoms, delay progression and reduce mortality

36
Q

What drugs are given to a patient diagnosed with heart failure?

A

- Furosemide loop diuretic to relieve symptoms

- ACEi (ramipril) and Beta blocker (bisoprolol) to reduce heart rate, b.p and therefore the work load and oxygen demand of the heart

- Spironolactone if needed as refractory hyperaldosteronism may occur

  • Statins if heart failure due to MI
37
Q

Why are older and black patients treated with CCBs rather than ACEi’s for hypertension initially?

A

These populations have lower renin levels

38
Q

What drug treatment would you consider at this stage?

A

Post MI bundle:

- Beta blocker (be careful as asthmatic)

  • ACEi
  • High dose statin
  • Antiplatelet
39
Q

What should your plan of action be for the following clinic blood pressures:

  • <140/90
  • 140/90 to 179/110
  • 180/20 or more
A
40
Q

What are some actions of ACEi’s that lower blood pressure?

A
  • Less vasoconstriction
  • Less sympathetic activity
  • Less aldosterone so less salt and water retention
41
Q

Which diureic is an add on therapy in resistant hypertension?

A

Spironolactone if patient has normal K+ levels. Thiazide already added in three step approach

42
Q

What are some drugs added in resistant hypertension, apart from a diuretic?

A

Beta Blocker (e.g bisoprolol): lowers renin levels, -ve chronotrope, decreases cardiac output

Alpha Blocker (doxazosin): causes vasodilation reducing PVR